This patch (as1188) combines the tests for decrementing a drive's
reported capacity and expands the comment. It also adds an
informational message to the system log, informing the user when the
reported value has been changed.
Signed-off-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
---
Note: This is a resend of a patch that was first submitted on December
15. I would like this change to appear in 2.6.30 because I have
another patch waiting that depends on it.
Index: usb-2.6/drivers/scsi/sd.c
===================================================================
--- usb-2.6.orig/drivers/scsi/sd.c
+++ usb-2.6/drivers/scsi/sd.c
@@ -1384,18 +1384,22 @@ repeat:
sd_read_protection_type(sdkp, buffer);
}
- /* Some devices return the total number of sectors, not the
- * highest sector number. Make the necessary adjustment. */
- if (sdp->fix_capacity) {
+ /* Some devices are known to return the total number of blocks,
+ * not the highest block number. Some devices have versions
+ * which do this and others which do not. Some devices we might
+ * suspect of doing this but we don't know for certain.
+ *
+ * If we know the reported capacity is wrong, decrement it. If
+ * we can only guess, then assume the number of blocks is even
+ * (usually true but not always) and err on the side of lowering
+ * the capacity.
+ */
+ if (sdp->fix_capacity ||
+ (sdp->guess_capacity && (sdkp->capacity & 0x01))) {
+ sd_printk(KERN_INFO, sdkp, "Adjusting the sector count "
+ "from its reported value: %llu\n",
+ (unsigned long long) sdkp->capacity);
--sdkp->capacity;
-
- /* Some devices have version which report the correct sizes
- * and others which do not. We guess size according to a heuristic
- * and err on the side of lowering the capacity. */
- } else {
- if (sdp->guess_capacity)
- if (sdkp->capacity & 0x01) /* odd sizes are odd */
- --sdkp->capacity;
}
got_data:
--
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